Vibration has been applied to the human body from time immemorial. Many patents exist for mechanical vibrating devices. The quintessential prototypes of these are devices of the asymmetric flywheel variety. Ordinary mechanical vibrating devices are used to relieve pain and induce relaxation. It is established that the effect of vibration is increased as the surface area of the human body exposed to vibration becomes greater. Unfortunately, mechanical vibrating devices when applied to a large surface area of the human body may cause motion sickness and other deleterious side effects because of infrasonic (less than 20 Hz) resonances inherent in their nonlinear design. In addition, all mechanical vibrating devices when applied to a specific point on the body for an extended period of time create numbness. The salutary effects sought after quickly fade because of “stimulus fatigue”, a phenomenon whereby repetitive stimulation of nerve endings ceases to be transmitted because the nerve fatigues. To overcome the cessation of nerve transmission using a mechanical vibrator requires exponentially increasing stimulus strength which is possible for only a limited time. Therefore, the sought after beneficial effect ceases due to the stimulus fatigue phenomenon.
Inventors and researchers have discovered that vibration created by music could be applied to the human body through devices such as simple speakers. This application of inserting speakers for the playing of music into sofas, chairs and pads can result in relaxation and pleasing sensation. U.S. Pat. No. 5,143,055, for example, discloses such a simple device. Any positive effect of such a device will be random depending upon the chosen music.
U.S. Pat. No. 5,101,810 teaches that specific sound frequencies in the range of 30 to 120 Hz can be embedded in music and transmitted to the human body through loud speakers to massage a specific portion of the human body or to treat specific bodily complaints. The specific sine wave frequency (for example, 39 Hz) would become tedious and boring if it was not embedded in music. For this reason the method of this patent is always used in conjunction with music. Separate ambient speakers and amplifiers are used for the accompanying music. U.S. Pat. No. 5,101,810 specifies the use of two or more loud speakers playing through two channels. One channel is used for auditory stimulation with this chosen music. The second channel generally plays through a speaker(s) affixed to a bed or chair upon which the subject lies. The frequency chosen for application to the subject is embedded in the music played through that affixed speaker(s). Earlier tapes generally contained only one embedded frequency. Later tapes sometimes contained several frequencies embedded in different parts of the music to relieve monotony or to stimulate another muscle or nerve. The low frequency sine wave signal is further made more palatable by administering it in pulsatile form. The pulse is created and its duration determined by phase cancellation mixing the desired frequency with another frequency very close to it. For example, mixing a 60-hertz frequency with a 60.07 Hz frequency would generate a pulsatile signal of approximately 14 seconds duration. According to the “resonance theory”, the teaching of U.S. Pat. No. 5,101,810 faces limitations in scanning ability inherent in the use of the “phase cancellation”. In practice it is limited to the effect generated by the specific frequency implanted in the music. The system is expensive to implement. It requires a therapist/technician to operate a sine wave generator. The technician must have sufficient training to determine appropriate frequencies and implant them in the music for each patient.
The frequencies recommended in of U.S. Pat. No. 5,101,810 are anatomic in nature. Different frequencies are chosen according to the specific muscle or the disease process to be treated. The specific frequency within the ranges broadly specified below is determined by using a sine wave generator to test each subject on a sound bed. This frequency is implanted into music. Below is Skille's (one of the inventors of U.S. Pat. No. 5,101,810) recommendation of ranges from which to choose a specific frequency for a cited problem.
ConditionFrequency 1. Spastic Conditions 1. 40-60 Hz 2. Premenstrual Tension 2. ~50 Hz 3. Back Pain 3. ~50 Hz 4. Asthmatic Conditions 4. 40-70 Hz 5. Sports 5. 40-60 Hz 6. Muscle Cramps and Pain 6. 40-90 Hz 7. Different Stress Problems 7. 40-70 Hz 8. Insomnia 8. 40-70 Hz 9. Rheumatic Conditions 9. 40-90 Hz10. Frozen hand and feet10. 40-60 Hz11. Headache11. 60-90 Hz12. Multiple Sclerosis12. 40-60 Hz
This method is criticized in U.S. Pat. No. 5,113,852 as not addressing the problem of “stimulus fatigue”.
To address this problem U.S. Pat. No. 5,113,852 provides a procedure for applying vibration acoustically to the human body by means of vibrating elements to produce a pleasant feeling for the relaxation of the body, each of such vibrating elements being vibrated at a single audio frequency in the range of 20 Hz to 200 Hz with the vibrating elements arranged in a substantially linear array, so that each of the vibrating elements may be adjacent to a specific region of the human body. U.S. Pat. No. 5,113,852 then specifies cyclically and continuously varying the intensity of vibration of each of the vibrating elements periodically between maximum and minimum values other than zero to generate an intensity maxima at a predetermined frequency of occurrence and further driving each of the vibrating elements at different times by providing a phase difference between the intensity maxima generated by the adjacent of the vibrating elements, so that the intensity maxima may occur successively in adjacent ones of the vibrating elements along the linear array to produce the sensation of the wave traveling along the human body. The method of this patent is effective. It addresses the problem of “stimulus fatigue” by moving an audio frequency to each of this series of linearly arranged vibrating elements with a predetermined time delay which provides actual motion of the signal and temporal relief for the various parts of the human body being intermittently vibrated.
It is recognized that specific parts of the body respond to specific frequencies. For example the great muscles of the back are generally stimulated by frequencies in the 50-hertz range. It is also known that to achieve the same locus of sensation in a different subject or in the same subject at a different time, the frequency may have to be changed by several Hz. If one were to accept the “resonance theory”, this could be the result of natural changes in hydration state changing the thickness of the tubular structure (muscle or nerve) to be vibrated. In my experimental practice of the method of U.S. Pat. No. 5,113,852, very small frequency variations in the phase program passing through each element have been used to allow a single tape or program to be used to stimulate the same body part for multiple patients. This is to accommodate small individual differences in resonance frequencies. If one wishes to stimulate relaxation of the central nervous system, it is known that the brain generates oscillating waves at 40 Hz. There is a small variation between individuals. Using the “resonance theory” one would wish to set up a resonance between the vibratory elements and the subject's brain. The sine wave stimulation program passing through each vibratory element may scan between 39 and 41 Hz. The effect of this scanning is the ability to achieve a resonance frequency in a higher proportion of treated subjects.
The afore-described patents disclose the physiologic use of only a narrow frequency range. This is because sounds above 120 Hz are better heard than felt. Using conventional speakers to produce sufficient air pressure to generate tactile sensations from frequencies as high as 800 Hz would create auditory damage. Baseshakers previously described in U.S. Pat. No. 4,326,506 are very limited in range, generally well under 100 Hz. Beyond a very narrow frequency band they are generally deficient in quality waveform reproduction when observed on an oscilloscope. For example, the Aura™ Baseshaker (U.S. Pat. No. 4,326,506) has a very narrow band, centered around 40 Hz, within which it can reproduce low frequency waves accurately. Even marginally acceptable reproduction tops out at about 100 Hz.
In practice almost all programs following the teachings of U.S. Pat. Nos. 5,101,810 and 5,113,852 have been written for frequencies below 70 Hz. Conventional speakers are very limited in their ability to produce significantly tactile sound in frequencies higher than 120 Hz. With conventional speakers pleasureability for most people disappears above 70 Hz.
Until the subject invention, no one had solved the problem of “stimulus fatigue” to attain long-term beneficial effects through the vibration of the human body using a method that required only a simple inexpensive point source vibratory element. It would obviously be desirable to develop a simple, cost-efficient method to address the problems of “stimulus fatigue” and to attain long-lasting benefits of therapeutic vibrational massage. It would also be desirable to broaden the frequency ranges possible for therapeutic tactile sound or sine wave massage.